Yesterday morning, my son Samuel had an appointment at the Evelina children's hospital in London. We arrived early and saw the TV crews and their vans just around the corner, so went over to watch David Cameron's speech that was being shown in one of the TV vans.

I, and many other parents of children with special educational needs, have been concerned about the pledge in the Tory manifesto to "end the bias towards the inclusion of children with special needs in mainstream schools". We personally had to battle for two years to get our son into our local school, which his two sisters attend.

It cost us thousands of pounds to go to a tribunal, which we then won. The local authority then said they would appeal against the decision to the high court. At that point, the secretary of state intervened, and paid for some modifications to the school. Samuel now attends the school.

To say that there is a "bias toward the inclusion of children with special educational needs" is to entirely misunderstand what is actually going on. Cameron said, during our exchange this morning, that he had written that part of the manifesto himself. He also spoke of his own experience with his son.

I have absolutely no doubt that Cameron's heart is in the right place, and have immense sympathy for what his has experienced personally. But I also believe that his own experience should not be the main determinant of his party's position.

This, at the end of the day, is a question of both resourcing and culture. Either we are for inclusion or we aren't. To include children with special needs in mainstream schools takes commitment and a lot of work. Indeed, it requires "bias" – which has actually been lacking in the education system, despite all the talk of inclusion from Labour.

There are few parents of children with special educational needs who would not want their children to attend their local school with brothers and sisters and friends, provided that the school is properly resourced, equipped and able to successfully include their children.

The problem of the last few years has been that mainstream schools have not been equipped well enough to be able to show parents and others that they work for children with special educational needs. The move toward inclusion has been half-hearted. Many parents have been let down, and many feel therefore that they have to opt for special schools. It is the symptom, rather than the actual underlying problem, which David Cameron is seeking to address. Indeed, he has made a misdiagnosis of what is actually going on, which will have a direct impact on many families.

Cameron has offered to meet me and discuss it further. I have asked that I bring other parents whose experience is like mine, from groups such as Parents for Inclusion. But this, in many senses, is too late. The Tories are right now seeking election on their manifesto pledge.